The present invention relates to fluid sampling apparatus generally, and particularly to apparatus for sampling blood from a puncturable conduit.
Various types of apparatus for sampling fluids are known. In particular, various types of blood sampling devices are known in the art. The following patent documents are believed to represent the most relevant prior art: U.S. Pat. No. 3,841,835 to Kishimoto et al., U.S. Pat. No. 3,877,465 to Miyake, U.S. Pat. No. 4,266,543 to Blum, U.S. Pat. No. 4,843,017 to Oberhardt et al., and U.S. Pat. No. 5,360,012 to Ebara et al., and PCT Published Patent Application WO 97/45714, which is assigned to the present assignee.
A problem with current blood sampling devices is that they incorporate a latex sheath-covered needle. The latex recedes to the bottom of the needle during blood sampling with a vacuum tube, thus exposing the needle point. It retracts to cover the needle when the sampling tube is withdrawn, thus preventing blood from leaking out of the needle. As latex sheaths are not robust articles, they will often fail to retract, resulting in donor blood leakage. It would be desirable, therefore, to have a blood sampling apparatus in which the need for a needle cover sheath is obviated.
A problem also exists in donation of blood for which the prior art has no known convenient and economical solution. Often when blood is drawn from a donor the very first amount of blood may have bacterial contamination, for example, due to bacteria or other germs found on the skin of the donor which can enter the blood upon puncturing the skin. Accordingly, it would be desirable to separate this first quantity of blood from the blood collected in a donor bag. In many prior art sampling systems, a permanent disturbance (such as a needle tip) is introduced into the blood stream, causing turbulence and coagulation. Therefore, they are suitable only for sampling after donation and not for first blood collection.
The present invention seeks to provide novel and easy-to-use blood sampling apparatus for use with puncturable conduits, and which solves the abovementioned problems. In the present invention, a blood donor is attached to conventional blood donation apparatus including a blood conduit which leads drawn blood into a sterile blood bag. The sampling apparatus of the present invention is attached to the blood donation apparatus and permits, if desired, selectively diverting an initial, small quantity of blood at the beginning of blood donation into a sealed vacuum tube. This initial quantity which can contain bacterial contamination is thus diverted from the main collected blood volume. It is a particular feature of the present invention that the sampling apparatus diverts the flow of blood from the blood conduit without disturbing the continuity of blood flow towards the donor bag. Any number of vacuum tube samplings can be drawn with the present invention, and, of course, the blood can be drawn into the vacuum tube at any time other than that of the initial quantity.
In one preferred embodiment of the present invention, a vacuum tube is brought into puncturing engagement with the blood conduit by pushing the vacuum tube against a spring in the sampling apparatus. A flexible, elastomeric ring fixedly grips the head of the vacuum tube during drawing of blood thereinto. The sampling apparatus preferably contains no latex and includes embodiments which can be sterilized either with steam or ethylene oxide (ETO).
There is thus provided in accordance with a preferred embodiment of the present invention fluid sampling apparatus including an elongate housing including a conduit puncturing portion at a distal end thereof, the conduit puncturing portion being adapted to receive therein a puncturable conduit, a needle mount slidingly mounted in the elongate housing, a double-pointed needle adapted for flow of fluid therethrough, the needle being fixedly mounted in the needle mount with a proximal point extending proximally outwards of the needle mount and a distal point extending distally outwards of the needle mount, a seal plug mounted in the distal portion of the housing, the seal plug being aligned with the needle such that the distal point can pierce through the seal plug into a puncturable conduit, and a biasing device positioned between the seal plug and a distal face of the needle mount, the biasing device having a first position wherein the distal face of the needle mount is spaced from the seal plug and the distal point of the needle does not distally protrude through the seal plug, and the biasing device having a second position wherein the needle mount is slid distally and the distal point distally protrudes through the seal plug and can pierce a puncturable conduit received in the conduit puncturing portion.
In accordance with a preferred embodiment of the present invention in the first position the biasing device is in a non-compressed state, and in the second position the biasing device is in a compressed state. Preferably the biasing device includes a spring.
Further in accordance with a preferred embodiment of the present invention a clamp extends from the conduit puncturing portion.
Still further in accordance with a preferred embodiment of the present invention the needle mount includes a disc radially extending therefrom and the housing includes a distal shoulder against which the disc can abut in the second position.
Additionally in accordance with a preferred embodiment of the present invention a flexible ring is mounted in the housing operative to grip a head of a vacuum tube inserted through a proximal end of the housing. The disc of the needle mount can proximally slidingly abut against the flexible ring.
In accordance with a preferred embodiment of the present invention the housing includes two portions attached together and sealed by the flexible ring.
Further in accordance with a preferred embodiment of the present invention the needle mount is slidingly mounted in the elongate housing by means of a tongue-and-groove slider which substantially prevents rotation of the needle about its longitudinal axis.
Still further in accordance with a preferred embodiment of the present invention a proximal end of the housing is sealed by a cap. The cap may be integrally formed with the housing.
Additionally in accordance with a preferred embodiment of the present invention one or more tabs radially extend from an outside surface of the housing.
In accordance with a preferred embodiment of the present invention the fluid sampling apparatus is autoclavable.